The thrill of a perfectly manicured lawn can quickly turn to frustration when your lawnmower sputters to a halt. One of the most common culprits? A faulty ignition coil. This vital component delivers the spark that ignites the fuel, and when it’s not working properly, your mower simply won’t start.
But don’t despair! Understanding how to check your lawnmower coil can save you a trip to the mechanic and a hefty repair bill. This guide will walk you through the process, explaining the tools you’ll need, the steps involved, and the signs that indicate a faulty coil. So, grab your tools, let’s dive in and get your mower back in action!
Understanding the Lawn Mower Ignition Coil
The ignition coil is a transformer that converts low-voltage electrical current from your battery into high-voltage current, creating the spark needed to ignite the fuel-air mixture in your engine. It works in conjunction with the spark plug, the distributor (if your mower has one), and the ignition switch.
Here’s a simplified explanation of how it works:
- Battery Provides Power: The battery sends a low-voltage signal to the ignition coil.
- Coil Energizes: The coil’s windings create a magnetic field, storing energy from the battery.
- Spark Plug Fires: The ignition switch signals the coil to release the stored energy, generating a high-voltage spark that jumps across the gap of the spark plug.
- Fuel Ignites: The spark ignites the fuel-air mixture, powering the engine.
Troubleshooting: When to Suspect a Faulty Coil
Before you dive into checking the coil itself, it’s crucial to recognize the symptoms that suggest a problem with this component:
- No Start: The most obvious sign is your lawnmower not starting at all. This can be due to several factors, but a faulty coil is a common culprit.
- Engine Cranking But Not Starting: If you hear the engine cranking but it doesn’t fire up, it could point to a lack of spark, which the coil is responsible for.
- Sporadic Starting Issues: If your mower starts sometimes and other times it refuses to, this could be an indication of a weak or failing coil.
- Backfiring or Rough Running: These symptoms might suggest a problem with the ignition system, including a faulty coil.
Important Note: These symptoms can also be caused by other issues, such as a bad spark plug, faulty wiring, or a fuel problem. So, it’s essential to systematically troubleshoot before focusing solely on the coil.
Tools and Supplies
Before you begin, gather these essential tools:
- Multimeter: A digital multimeter is a must-have for electrical testing.
- Spark Plug Socket: This tool helps you remove and install the spark plug safely.
- Spark Plug Wrench: A spark plug wrench is needed to tighten and loosen the spark plug.
- Wire Strippers: Used to remove insulation from wires for testing.
- Test Leads: Used to connect the multimeter to the coil and other components.
- Safety Glasses: Protect your eyes from debris and sparks.
- Work Gloves: Protect your hands.
Checking the Lawn Mower Coil: A Step-by-Step Guide
Now that you’re equipped, let’s check that coil!
1. Disconnect Battery: Before you start, always disconnect the battery to prevent electrical shocks. Locate the battery terminals and use a wrench to loosen the negative (usually black) terminal first, then the positive (usually red) terminal.
2. Inspect the Coil:
- Visually Inspect: Look for any signs of damage, such as cracks, burns, or corrosion on the coil housing or wires.
- Check for Loose Connections: Make sure all the connections to the coil are secure.
3. Test the Coil with a Multimeter:
- Resistance Test: Set your multimeter to the ohms (Ω) setting. Connect the multimeter probes to the coil terminals (usually marked as primary and secondary). Refer to your mower’s manual for the specific resistance values for your coil model. If the resistance is outside the specified range, the coil is likely faulty.
- Continuity Test: Using the multimeter in continuity mode, test for continuity between the primary and secondary terminals. You should get a reading of continuity (usually indicated by a beep). If there is no continuity, the coil is likely broken.
4. Test the Spark Plug:
- Remove the Spark Plug: Use your spark plug socket to remove the spark plug.
- Check for Spark: Connect the spark plug wire to the spark plug. Ground the spark plug by holding it against the engine block. Have someone crank the engine while you observe the spark plug. A bright blue spark indicates a healthy spark plug, while a weak or no spark points to a problem with the ignition system.
5. Check the Spark Plug Wire:
- Visual Inspection: Look for any signs of damage, cracks, or fraying in the wire insulation.
- Continuity Test: Use your multimeter in continuity mode to check for continuity within the wire.
6. Test the Ignition Switch:
- Locate the Ignition Switch: Find the ignition switch on your mower.
- Continuity Test: Use your multimeter to check for continuity between the switch terminals when the switch is in the “on” position.
7. Check the Wiring:
- Visually Inspect: Check all the wires connecting to the coil, spark plug, ignition switch, and other components for any signs of damage, corrosion, or loose connections.
- Continuity Test: Use your multimeter in continuity mode to test each wire for continuity.
8. Reassemble and Test:
- Reconnect Battery: After you’ve completed all the tests and ensured there are no issues, reconnect the battery terminals. Start with the positive terminal first, then the negative terminal.
- Test Your Mower: Try starting your mower. If it starts and runs smoothly, the coil is likely not the culprit. If the problem persists, you’ll need to address the remaining components.
Important Tip: If you’re unsure about any of the testing procedures or are uncomfortable working with electrical components, it’s always best to consult a qualified mechanic.
Troubleshooting a Faulty Coil
Once you’ve identified a faulty coil, you have two main options:
- Replacement: This is the most common solution. Locate a replacement coil that’s compatible with your mower model. Be sure to get the correct type (single or dual), voltage, and resistance rating.
- Repair: In some cases, coils might be repairable, but this is usually not recommended for most lawnmower coils. It’s often more cost-effective and less time-consuming to simply replace the faulty component.
Remember: When installing a new coil, always follow the manufacturer’s instructions carefully. Pay close attention to the wire connections and ensure they are properly secured.
Preventive Maintenance
Maintaining your lawnmower coil can help extend its lifespan:
- Regular Cleaning: Keep the coil clean and free of dirt and debris.
- Inspect Regularly: Visually inspect the coil for any damage or signs of wear.
- Replace as Needed: If you notice any signs of wear or damage, replace the coil promptly.
Conclusion
Troubleshooting a lawnmower coil might seem daunting, but with the right tools and knowledge, it’s a task you can tackle yourself. By following these steps, you can diagnose a faulty coil and either repair or replace it, getting your mower back to mowing those lawns in no time.
Remember, if you’re unsure about any of the steps or encounter any unexpected problems, don’t hesitate to consult a qualified mechanic for assistance. Now go out there and conquer those overgrown lawns with confidence!
FAQ
Q1. What is a lawnmower coil and what does it do?
The ignition coil is a crucial component in your lawnmower’s ignition system. It’s a small, cylindrical component that transforms the low voltage from the battery into a high-voltage electrical current needed to spark the spark plug, igniting the fuel-air mixture in the combustion chamber. Without a functioning coil, your lawnmower won’t be able to start.
Essentially, the coil acts as a transformer, stepping up the voltage to create a powerful spark that ignites the fuel. This spark is essential for the combustion process that powers your lawnmower.
Q2. Why might my lawnmower coil fail?
Several factors can contribute to the failure of your lawnmower coil. One common culprit is age. Over time, the coil’s internal windings can degrade and become brittle, leading to short circuits or open circuits.
Additionally, exposure to moisture, vibration, and excessive heat can also damage the coil. Moisture can cause corrosion and short circuits, while vibration can loosen internal connections. High temperatures can accelerate the degradation of the coil’s insulation.
Q3. What are the symptoms of a faulty lawnmower coil?
A faulty lawnmower coil can exhibit several symptoms that can help you diagnose the issue. One common indicator is difficulty starting the engine. The engine might crank but not fire, or it might sputter and die shortly after starting.
Another telltale sign is a lack of spark at the spark plug. If you’re able to test the spark, you’ll notice a weak or absent spark if the coil is malfunctioning. If you’re unsure, it’s best to consult a repair manual or seek professional assistance.
Q4. How can I test my lawnmower coil?
To test your lawnmower coil, you’ll need a few basic tools, including a multimeter, a spark plug wire, and a grounded metal object. First, disconnect the spark plug wire from the spark plug and ground it to the metal object.
Next, connect the multimeter to the spark plug wire and the other probe to the metal object. Crank the engine and observe the multimeter reading. If the coil is functioning correctly, you should see a high-voltage reading on the multimeter. If the reading is low or absent, the coil is likely faulty.
Q5. Can I replace the coil myself?
Replacing a lawnmower coil is a relatively simple task that many DIYers can handle. It involves removing the old coil, disconnecting the wires, and installing the new coil in the same location.
You’ll need a basic toolkit, including screwdrivers and a wrench. It’s important to refer to your lawnmower’s repair manual for specific instructions and to ensure you have the correct replacement coil for your model.
Q6. What should I do if I’m not comfortable replacing the coil myself?
If you’re not comfortable working on your lawnmower or don’t have the necessary tools, it’s best to consult a qualified lawnmower repair technician. They can diagnose the problem, replace the coil, and ensure that your lawnmower is operating safely and efficiently.
Taking your lawnmower to a professional also ensures that you receive the correct replacement part and that the installation is done properly. This can prevent future issues and save you time and money in the long run.
Q7. What precautions should I take when working with a lawnmower?
Before working on your lawnmower, it’s crucial to take some safety precautions. Always disconnect the spark plug wire and the battery terminals to prevent accidental ignition.
Additionally, work in a well-ventilated area and wear appropriate safety gear, such as gloves, eye protection, and closed-toe shoes. Never attempt repairs while the engine is running. Always follow the safety instructions in your lawnmower’s manual.